The interpeduncular fossa is a deep depression of the ventral surface of the midbrain between the two cerebal crura.

[1][2][3] It has been found in humans and macaques, but not in rats or mice, showing that this is a relatively new evolutionary region.

[3][6] The ventral tegmental area lies at the depth of the interpeduncular fossa.

[5] The floor of interpeduncular fossa, from behind forward,[citation needed] are the posterior perforated substance,[2] corpora mamillaria, tuber cinereum, infundibulum, and pituitary gland.

[citation needed] Contents of interpeduncular fossa include oculomotor nerve, and circle of Willis.